Contact breaker assembly with improved adjustable distributor mounting plate and locking plate means

ABSTRACT

A contact breaker assembly for use in the ignition system of an internal combustion engine includes a mounting plate arranged to mount the contact breaker assembly adjacent a rotatable cam. An angle plate is supported on one face of the mounting plate and the angle plate carries a fixed electrical contact and also pivotally supports an insulating heel member carrying a movable contact. The insulating heel member includes a cam follower engageable by the cam in use, and resilient means urges the heel member to pivot in a direction towards the cam so as to engage the movable contact with the fixed contact. A locking plate is engaged with the face of the mounting plate remote from the angle plate and a pivot post extends between the locking plate and the angle plate through the mounting plate, the pivot post positioning the angle plate for pivotal movement relative to the mounting plate about the axis of the heel member. First and second rotatable eccentric adjustment devices act between the angle plate and the mounting plate and are operable respectively to move the angle plate relative to the mounting plate in a manner to adjust the position of the cam follower of the heel member around the periphery of the cam and towards and away from the cam. Locking screws are provided to lock the angle plate against movement relative to the mounting plate.

nited States Patent 1191 Mushy 1451 July 10,1973

1 1 CONTACT BREAKER ASSEMBLY WITH IMPROVED ADJUSTABLE DISTRIBUTORMOUNTING PLATE AND LOCKING PLATE MEANS [75] lnventor: Geoffrey RalphMosby, Sutton Coldfield, England [73] Assignee: Joseph Lucas(Industries) Limited,

Birmingham, England [22] Filed: Nov. 22, 1971 [21] Appl. No.: 200,707

[30] Foreign Application Priority Data NOV. 24, 1970 Great Britain55,722/70 52 US. (:1 .f. 200/31 A, 200/19 R, 200/31 DP 51 1111. c1.110111 9/02 [58] Field of Search 200/19 R, 19 A, 30 R, 200/30 A, 31 DP,31 A, 31

[56] References Cited UNITED STATES PATENTS 2,847,524 8/1958 Slick200/30 A 2,854,534 9/1958 Beauclair 200/30 A 2,914,625 11/1959 Heveran200/31 2,730,583 1/1956 Brunk 200/31 2,835,755 5/1958 Filko 200/31 x3,510,609 5/1970 Cooksey 200/19 A Primary Examiner.l. R. ScottAttorney-Holman & Stern [5 7] ABSTRACT A contact breaker assembly foruse in the ignition system of an internal combustion engine includes amounting plate arranged to mount the contact breaker assembly adjacent arotatable cam. An angle plate is supported on one face of the mountingplate and the angle plate carries a fixed electrical contact and alsopivotally supports an insulating heel member carrying a movable contact.The insulating heel member includes a cam follower engageable by the camin use, and resilient means urges the heel member to pivot in adirection towards the cam so as to engage the movable contact with thefixed contact. A locking plate is engaged with the face of the mountingplate remote from the angle plate and a pivot post extends between thelocking plate and the angle plate through the mounting plate, the pivotpost positioning the angle plate for pivotal movement relative'to themounting plate about the axis of the heel member. First and secondrotatable eccentric adjustment devices act between the angle plate andthe mounting plate and are operable respectively to move the angle platerelative to the mounting plate in a manner to adjust the position of thecam follower of the heel member around the periphery of the cam andtowards and away from the cam. Locking screws are provided to lock theangle plate against movement relative to the mounting plate.

10 Claims, 4 Drawing Figures Painted July 10, 1973 I 3,745,272

2 Shoots-Shut 1 Patented M 10, 1913 3,745,212

2 Slain-Shut 2 CONTACT BREAKER ASSEMBLY WITH IMPROVED ADJUSTABLEDISTRIBUTOR MOUNTING PLATE AND LOCKING PLATE MEANS This inventionrelates to a contact breaker assembly for use in the ignition system ofan internal combustion engine.

An assembly according to the invention includes, a mounting platearranged to mount the assembly adjacent a rotatable cam in use, an angleplate supported on one face of the mounting plate, the angle platecarrying a fixed electrical contact and having pivotally ri'iountedthereon an insulating heel member having a cam follower engageable bysaid cam in use, the heel member carrying a movable contact and theassembly having resilient means urging the heel member in a directiontowards the cam to engage the movable contact with the fixed contact, alocking plate engaged with the other face of the mounting plate, a pivotpost extending between the locking plate and the angle plate andmounting the-angle plate for pivotal movement about the pivotal axis ofthe heel member, a first adjustment device acting between the angleplate and the mounting plate and operable to move the angle plate andthe locking plate relative to the mounting plate in a manner to adjustthe position of the cam follower of the heel member around the peripheryof the cam, and locking means operable to lock the angle plate againstmovement relative to the mounting plate.

Preferably the assembly includes a second adjustment device actingbetween the angle plate and the mounting plate and operable to move saidangle plate about the axis of said pivot post relative to said lockingplate and said mounting plate in a manner to move said cam followertowards or away from said cam.

Desirably means is provided whereby the locking plate can be fixedrelative to the mounting plate at least during operation of the secondadjustment device.

Conveniently said means is defined by a bolt or screw extending througha slot in the mounting plate and engaged with the locking plate.

Desirably said bolt or screw also constitutes said pivot post.

Preferably the first and second adjustment devices are defined by firstand second members rotatably mounted on the angle plate and havingeccentric portions engaged in respective apertures in the mountingplate.

Conveniently the first and second rotatable member have associatedtherewith respective locking means capable of locking the memberrespectively against rotation relative to the angle plate.

Preferably said mounting plate isannular and is arranged to encirclesaid cam in use, the mounting plate also carrying a second angle platehaving pivotally mounted thereon second insulating heel member having acam follower engageable by the cam and the second heel member carrying asecond movable contact engageable with a second fixed contact carried bythe second angle plate, the second angle plate being mounted on themounting plate for pivotal movement relative thereto about the pivotalaxis of the second heel member, and there being provided a thirdadjustment device operable to pivot the second angle plate relative tothe mounting plate, and further locking means operable to fix the secondangle plate relative to the mounting plate.

Desirably the second cam follower is displaced from the first mentionedcam follower by approximately around the mounting plate.

One example of the invention is illustrated in the accompanying drawingswherein:

FIG. 1 is a plan view of a contact breaker assembly,

FIG. 2 is a sectional view on the line 22 in FIG. 1,

FIG. 3 is a sectional view on the line 33 in FIG. 1, and

FIG. 4 is a plan view of the mounting plate of the assembly.

Referring to the drawings, the assembly includes a mounting plate 11which is arranged to be secured in the casing of a magneto of theignition system of an internal combustion engine. It will be appreciatedhowever that the assembly to be described is equally applicable toignition systems utilizing ignition distributors, wherein the plate 11will be arranged to be mounted within the casing of the ignitiondistributor. In either case the operating cam of the magneto, orignition distributor will extend through a central, circular aperture 12in the plate. Supported on one face of the plate 11 is a metal angleplate 13 upstanding from which is a hollow cylindrical sleeve 14 whichsupports an insulating heel member 15. The heel member 15 is pivotallymounted on the sleeve 14, and includes a cam follower 16 which isengageable with the cam surface of the rotatable cam of the magneto.Secured to the heel 15 is a movable electrical contact 17 the contact 17being electrically connected to a conductive leaf spring 18 which at itsend remote from the contact 17 is anchored to an insulating support 19upstanding from the plate 13. The support 19 is arranged to receiveterminals whereby electrical connections can be made to the movablecontact 17. The heel member 15 is moulded in insulating material, and soinsulates the moving contact 17 from the plate 13. The leaf spring 18urges the heel member 15 to pivot about the sleeve 14in a direction tomove the cam follower 16 towards the cam of the magneto, and to engagethe moving contact 17 with a fixed contact 21 supported on, andelectrically connected to a peg integral with the angle plate 13.

Engaged with the opposite surface of the mounting plate 11 is a lockingplate 22 in the form of an elongated metal strip. In screw-threadedengagement with the plate 22, and extending through an arcuate slot 230in the mounting plate 11 is a screw 23 having a cylindrical head 24which engages the mounting plate 11 and which extends upwardly through ahole in the plate 13 and into the sleeve 14. The screw 23 serves thedouble function of acting as locking means capable of locking the plate22 in position relative to the plate 11 and also acting as a pivot postabout which the plate 13 can pivot relative to the plates 11, 22. Asstated above, the slot 23a in the plate 11 through which the screw 23extends, is arcuate, the slot being an are having its center ofcurvature coincident with the center of the circular aperture 12 in theplate 11.

Extending through the plates 11 and 13 are a pair of locking screws 26and 27 respectively. The heads of the screws 26, 27 engage the surfaceof the plate 13, and the shanks of the screws 27 are inscrew-threadedengagement with the plate 22. Thus when the screws 26, 27are tightened the plates 22 and 13 are locked in position relative tothe plate 11. The screws 26, 27 pass through respective elongated slotsin the plate 13, the elongated slots in the plate 13 extending generallyradially with respect to the plate 11, and the screws 26, 27 also extendthrough respective arcuate elongated arcuate slots 26a, 27a in the plate11, the slots 26a, 27a having their centers of curvature coincident withthe center of the aperture 12.

Mounted for rotation on the plate 13 are first and second adjustingdevices 28, 29 respectively. The devices 28, 29 are identical, and soonly the device 29 will be described. The device 29 includes a screwthreaded shank 31 which extends through a clearance hole 32 in the plate13. The plate 13 is formed with a recess in its lower surface withinwhich a disc like portion 33 integral with the shank 31 is located.Extending downw ardly from the portion 33 is a cylindrical projection34, the projection 34 being off-set from the axis of the shank 31 so asto constitute an eccentric. The portion 34 is engaged in an elongatedarcuate slot 34a in the plate 11, the slot 34a in the plate 11 beingdisposed with its center of curvature coincident with the center of theaperture 12. Engaged with the portion of the shank 31 of the device 29,where the shank 31 projects from the upper surface of the plate 13 is alock nut 35 which, when tightened against the plate 13 preventsrotational movement of the device 29 relative to the plate 13. Thearrangement of the device 28 is substantially identical, with theexception that the arcuate slot 30 in the plate 11 into which theeccentric portion of the device 28 extends, is disposed generallyradially of the plate 11.

It will be appreciated, that when the screws 26, 27 are relaxed, and thescrew 23 is tightened, then the plate 22 is fixed with respect to theplate 11, while the plate 13 can pivot about the axis of the screw 23,with respect to the plate 11. It will be noted that the axis of thescrew 23 is coincident with the axis of pivotal movement of the heelmember 15. With the parts in this condition, rotation of the shank ofthe device 29 causes the plate 13 to pivot about the axis of the screw23 relative to the plate 11, so that the cam follower 16 is movedtowards or away from the cam of the magneto. This operation permitsadjustment of the maximum operating gap which can occur between thefixed contact 21 and the movable contact 17 as the heel member isreciprocated by rotation of the cam.

When the device 29 has been operated, and the desired operating gapbetween the contacts 17, 21 has been achieved, the lock nut of thedevice 29 is tightened, to prevent further rotation of the device 29relative to the plate 1.3. The screw 23 can then be released, whereuponthe plates 13 and 22 will be free to move arcuately relative to theplate 11 about a center of curvature coincident with the center of theaperture 12 in the plate 11. The setting of the operating gap of thecontacts 17, 21 will not of course be lost since the device 29 waslocked in the desired position. Rotation of the device 28 causes sucharcuate movement of the plates 13 and 22, and thereby adjusts theposition of the cam follower 16 around the periphery of the cam of themagneto. Such movement of course adjusts the timing of the opening andclosing of the contacts 17, 21 in relation to the rotation of the cam.When the plates 13, 22 have been moved by the device 28 to give therequired timing the lock nut of the device 28 is tightened to preventfurther rotation of the device 28, and the screws 23, 26, and 27 aretightened to lock the plates 22, and 13, in position relative to theplate 11.

The plate 11 further serves to support a second angle plate 41 which ismounted on the plate 11 for pivotal movement about a pivot post 42extending upwardly from the plate 11. The pivot post 42 is fixed withrespect to the plate 11, and so the plate 41 cannot be moved arcuatelyon the plate 11, but can only pivot about the post 42. A further pair oflocking screws 43, 44 are provided for locking the plate 41 in positionrelative to the plate 11, and extending from the plate 41, co-extensivewith the post 42, and surrounding the post 42 is a hollow .sleeve 45upon which is pivotally mounted an insulating heel member 46. The heelmember 46 includes a cam follower 47 which is engageable with the cam ofthe magneto, and further carries a movable contact 48. The movablecontact is electrically connected to a conductive leaf spring 49 the endof which remote from the contact 48 is anchored to the plate 41 in amanner identical to that described with reference to the spring 18. Afixed contact 51 is supported on a tag integral with, and upstandingfrom the plate 41, and the contact 48 is movable into and out ofengagement with the contact 51 in response to rotation of the cam of themagneto. An eccentric mechanism 52 similar in operation to the devices28, 29, although without the provision of a lock nut is provided formoving the plate 41 about the pivot post 42 to adjust the maximumoperating gap of the contacts 48, 51. 2

When it is desired to set the operating gap and timing of both sets ofcontacts of the arrangement described above, the contact gap of thecontacts 38, 51 is first set by means of the eccentric device 52, andthe plate 41 is then locked in position relative to the plate 11. Theplate 11 is then moved relative to the cam of the magneto, to adjust thetiming of the operation of the contacts 51, 48. The operating gap of thecontacts 17, 21 is then set by means of the device 29, whereafter thelock nut of the device 29 is tightened to prevent alteration in the gapsetting, and the position of the cam follower 16 relative to the camfollower 47 around the periphery of the cam is adjusted by means of theadjusting device 28.

It will be appreciated that the arrangement described above could beincorporated in a conventional ignition distributor of a road vehicle,either with or without the provision of the contacts 48, 51 and theparts associated therewith.

I claim:

1. A contact breaker assembly for use in the ignition system of aninternal combustion engine, including, a mounting plate arranged to befixed adjacent a rotatable cam in use, an angle plate supported on oneface of the mounting plate, the angle plate carrying a fixed electricalcontact and having pivotally mounted thereon an insulating heel memberhaving a cam follower engageable by said cam in use, the heel membercarrying a movable contact and the assembly having resilient meansurging the heel member in a direction towards the cam to engage themovable contact with the fixed contact, a locking plate engaged with theother face of the mounting plate, a pivot post extending between thelocking plate and the angle plate and mounting the angle plate forpivotal movement relative to the mounting plate about the pivotal axisof the heel member, a first adjustment device acting between the angleplate and the mounting plate and operable to move the angle plate, thelocking plate and the pivot post relative to the mounting plate in anarcuate path to adjust the position of the cam follower of the heelmember around the periphery of the cam, first locking means operable tolock the locking plate and pivot post against movement relative to thelocking plate, a second lockable adjustment device acting between theangle plate and the mounting plate and operable to move the angle platerelative to the mounting plate about the axis of the pivot post so thatin use the operating gap of said fixed and movable contacts is adjusted,and, second locking means operable to lock the angle plate againstmovement relative to the mounting plate.

2. An assembly as claimed in claim 1 wherein said first locking means isdefined by a screw extending through a slot in the mounting plate andengaging the locking plate.

3. An assembly as claimed in claim 2 wherein said screw also constitutessaid pivot post.

4. An assembly as claimed in claim 1 wherein the first adjustment deviceis defined by a first member rotatably mounted on the angle plate andhaving an eccentric portion engaged in an aperture in the mountingplate.

5. Anassembly as claimed in claim 4 wherein said second adjustmentdevice is defined by a second member rotatably mounted on the angleplate and having an eccentric portion'engaged in an aperture in themounting plate.

6. An assembly as claimed in claim 5 wherein the first and secondrotatable members have associated therewith respective locking meanscapable of locking the member respectively against rotation relative tothe angle plate.

7. An assembly as claimed in claim 1 wherein said mounting plate isannular and is arranged to encircle said cam in use, the mounting platealso carrying a second angle plate having pivotally mounted thereonsecond insulating heel member having a cam follower engageable by thecam and the second heel member carrying a second movable contactengageable with a second fixed contact carried by the second angleplate, the second angle plate being mounted on the mounting plate forpivotal movement relative thereto about the pivotal axis of the secondheel member, and there being provided a third adjustment device operableto pivot the second angle plate relative to the mounting plate, andfurther locking means operable to fix the second angle plate relative tothe mounting plate.

8. An assembly as claimed in claim'7 wherein the second cam follower isdisplaced from the first mentioned cam follower by approximately aroundthe mounting plate.

9. An ignition distributor utilizing a contact breaker assemble asclaimed in claim 1.

10. A magneto utilizing a contact breaker assembly as claimed in claim1.

1. A contact breaker assembly for use in the ignition system of aninternal combustion engine, including, a mounting plate arranged to befixed adjacent a rotatable cam in use, an angle plate supported on oneface of said mounting plate, said angle plate carrying a fixedelectrical contact and having pivotally mounted thereon an insulatingheel member having a cam follower engageable by said cam in use, saidheel member carrying a movable contact and said assembly havingresilient means urging said heel member in a direction towards said camto engage said movable contact with said fixed contact, a locking plateengaged with the other face of said mounting plate, a pivot postextending between said locking plate and said angle plate and mountingsaid angle plate for pivotal movement relative to said mounting plateabout the pivotal axis of said heel member, a first adjustment deviceacting between said angle plate and said mounting plate and operable tomove said angle plate, said locking plate and said pivot post relativeto said mounting plate in an arcuate path to adjust the position of saidcam follower of said heel member around the periphery of said cam, firstlocking means operable to lock said locking plate and said pivot postagainst movement relative to said locking plate, a second lockableadjustment device acting between said angle platE and said mountingplate and operable to move said angle plate relative to the mountingplate about the axis of said pivot post so that in use the operating gapof said fixed and movable contacts is adjusted, and, second lockingmeans operable to lock said angle plate against movement relative tosaid mounting plate.
 2. An assembly as claimed in claim 1 wherein saidfirst locking means is defined by a screw extending through a slot insaid mounting plate and engaging said locking plate.
 3. An assembly asclaimed in claim 2 wherein said screw also constitutes said pivot post.4. An assembly as claimed in claim 1 wherein said first adjustmentdevice is defined by a first member rotatably mounted on said angleplate and having an eccentric portion engaged in an aperture in saidmounting plate.
 5. An assembly as claimed in claim 4 wherein said secondadjustment device is defined by a second member rotatably mounted onsaid angle plate and having an eccentric portion engaged in an aperturein said mounting plate.
 6. An assembly as claimed in claim 5 whereinsaid first and second rotatable members have associated therewithrespective locking means capable of locking said members respectivelyagainst rotation relative to said angle plate.
 7. An assembly as claimedin claim 1 wherein said mounting plate is annular and is arranged toencircle said cam in use, said mounting plate also carrying a secondangle plate having pivotally mounted thereon second insulating heelmember having a cam follower engageable by said cam and the second heelmember carrying a second movable contact engageable with a second fixedcontact carried by the second angle plate, the second angle plate beingmounted on the mounting plate for pivotal movement relative theretoabout the pivotal axis of the second heel member, and there beingprovided a third adjustment device operable to pivot said second angleplate relative to said mounting plate, and further locking meansoperable to fix said second angle plate relative to said mounting plate.8. An assembly as claimed in claim 7 wherein said second cam follower isdisplaced from said first mentioned cam follower by approximately 90*around said mounting plate.
 9. A contact breaker assembly as set forthin claim 1 for use in an ignition distributor.
 10. A contact breakerassembly as set forth in claim 1 for use in a magneto.